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High Fat and Fiber Rations: Effect on Growth, Metabolic and Exercise related Disorders. Amy M. Gill, Ph.D. Lexington, KY. EPIDEMIC!!. SENSITIVITY TO STARCH Insulin Resistance (IR), Equine Metabolic Syndrome(EMS), Cushing’s Disease (ECD), Developmental Orthopedic Disorder (DOD)
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High Fat and Fiber Rations: Effect on Growth, Metabolic and Exercise related Disorders Amy M. Gill, Ph.D. Lexington, KY
EPIDEMIC!! SENSITIVITY TO STARCH • Insulin Resistance (IR), • Equine Metabolic Syndrome(EMS), • Cushing’s Disease (ECD), • Developmental Orthopedic Disorder (DOD) • Laminitis, Colic • Exercise related disorders – RER, PSSM • Behavioral problems
Why are horses developing these problems? • ECS – older population? advanced vet care..or daily stress/starch in diet from young agealters normal hormonal profiles… • EMS – overweight population – “pear or apple shape” – similar to human diabetes – cortisol from the omentum
Why are horses developing these problems? • IR – why foals??? – survival mode – conserve body stores of energy…. • Mares – efficient placental transfer of glucose…… • Horses in training…too much stress (cortisol + starch..) • Excitable behavior – starch/confinement – “sugar buzz” - stress “From a digestive/hormonal standpoint, horses are not well equipped to digest and metabolize starches and sugars”
Horse’s Digestive Tract Non structural Carbohydrate Digestion Stomach 36% Small Intestines Caecum Fiber Digestion 64% Hindgut Colon Starch, Resistant starch, fructans, galactans…….
Endotoxins Laminitis Gas Colic Dehydration Events leading to Metabolic Disorders STARCH, FRUCTAN OVERLOAD or ORGAN FAILURE Gastrointestinal disturbance Lactic Acid pH Blood Flow Matrix Metalloproteinases(MMP’s) Kills Cecal “good” Bacteria Lactobacillus, Streptococcus increase Gut Motility Slows (Fermentation Continues)
Daily Episodic “Meal” feeding…. • Sub-clinical acidosis each time in sensitive individuals – leading to exercise, growth metabolic disorders? • Predisposing developing fetus to insulin resistance, DOD (endocrine imbalances)?
Increasing fat/digestible fiber in concentrates maintains the CALORIE content of the feed but reduces the percentage of starch in the total ration
Calorie Density - Fat vs. Oats 3 2.5 2 Relative 1.5 Calorie Oats Concentration 1 Fat 0.5 0 Ingredient Maintaining Body Condition in the Performance Horse Fat has 2.5 times as much calories per gram as oats
Vegetable fats • Highly digestible – vegetable highest, animal least (not recommended for horses) • Easily absorbed from small intestine • Bile from liver – adequate • Fats do not produce glycemic response • Highly palatable • Reduces excitability
Soluble Fiber – “Super Fibers” • Higher in energy than most long-stemmed forage, equal to that of oats • Lowers starch in the diet while maintaining high caloric level • Enhances microbial fermentation rate, thus improving digestion of other fiber, even mature (poorer quality) hay • Allows reduced hay feeding safely, if necessary
High fat/fiber feeds produce lower Glycemic Index Effect of different feedstuffs on blood glucose levels: • Grain meals raise blood glucose/insulin higher than forage • Adding fat/fiber reduces a feed’s glycemic index • Breed, age, sex, exercise can affect individual glyemic response
Glycemic – Index: Whole Oats 100 (standard) Beet Pulp (hydrated) 72.2Beet Pulp rinsed 34.1 Beet Pulp w/molasses 94.8Corn 104Sweet Feed (COB)107 Sweet Feed w/oil 52Timothy Hay 32 Alfalfa 52
Research - Glycemic Response • Pregnant mares fed high fiber/fat rations - lower glucose/insulin blood levels • Weanlings exhibiting high glycemic response - lower incidence of DOD when fed high fiber/fat concentrates • Yearlings fed high fiber/fat - more consistant growth curves • Yearlings fed high fiber/fat rations - better bone mineralization
ECD, EMS and IR: • All have insensitivity to insulin & aberrant carbohydrate metabolism • Cannot tolerate starches, sugars, fructans • Untreated horses eventually suffer laminitis
Managing Horses with Metabolic Disorders • MUZZLE when pastured • EXERCISE • Avoid starch, sugar in diet - grass and concentrates • Use supplement/forage, no concentrate • Feed more soluble fibers, moderate fat, mixed lower quality hay (but low NFC, NSC)
Developmental Orthopedic Disease • Physitis, Osteochondritis Dissecans, contracted tendons etc. • Large, rapidly growing foals • Erratic growth, trauma • Genetics, nutrition, exercise
Preventing DOD…. • Strive for moderate, steady growth rates
GROWTH – minimalADG for horse maturing at 500 kg • Weanling at 4 mos. - .85 kg (1.85 lbs) • Weanling at 6 mos. - .65 kg (1.45 lbs) • Yearling at 12 mos. - .50 kg (1.1 lbs) • Yearling at 18 mos. - .30 kg (0.66 lbs) • Two-year old - .20 kg ( .44 lbs)
Use scales or regression equation to estimate weight every month • weight = heartgirth (inches)2 X length (inches) 330 (mature horse) 280 weanling 301 yearling
DOD • Mineral imbalances Calcium - 0.8-1.0 % Phos. - 0.4-0.6 % Copper – 50 mg/kg feed Zinc -150 mg/kg feed • Protein - high levels less problem than low.
Osteochondritis Dissecans (OCD) • Foals between 3 and 12 months of age may be insulin resistant • OCD lesions most often occur during this time • Coincides with increase of “starch” consumption by foal.
OCD When a starch meal is fed: • Insulin/Growth Hormone secreted in response to elevated blood glucose • High Insulin concentration increases secretion of enzyme that causes temporary hypothyroxemia
Abnormal hormone secretion… • Elevated Insulin/Growth Hormone – continues to stimulate production of new cartilage • Low Thyroxine (T4) – halts the development of cartilage into bone • Lesions in cartilagemay be due the “arrested” conversion of cartilage into bone
DOD - how to manage nutritionallyFeedHigh fat/fiber feeds - minimize gluc./insulin changes after meal • Turn out - sprinting strengthens, remodels bone reduces insulin resistance • Weigh regularly • Free choice quality hay • Feed more frequent meals
Exertional or Recurrent Rhabdomyolosis (Tying Up), Polysaccharide Storage Myopathy (PSSM) • TB’s - muscle contractility/ca regulation - Abnormal excitation-contraction • Fillies – Hormonal, NERVOUS • Insulin resistance • Draft, QH, abnormal polysaccharide formation/storage
Equine Gastric Ulcer Syndrome (EGUS) • 90 % of performance horses combat ulcers • Foals can be affected • Habitat induced • Non-glandular portion of stomach affected by constant acid production
EGUS • Forages - produces saliva - provides buffering • Avoid high grain-low forage diets • Hand graze stall bound horses several times/d • Feed forages, high fat/fiber concentrates, increase frequency, - turn out!!!!
Summary • Maximize use of forages • Utilize high fat/fiber concentrates or supplement • Control intake of resistant starches and sugars • Strive for steady, moderate growth rate in growing horses • Reduce STRESS!